[buzzinhalfdozen]

This may be an odd question, but why would you leave water in any engine, the minerals in water attack almost every part of the cooling system. My suggestion (take it for what it's worth) drain the block and rad. go buy 2 gals. of premix antifreeze and pour it in, this would eliminate the potential for freezing and the antifreeze helps stop the errosion effects of water. Joe.....P.S. I've been told by may Rad. manufactures that you should use distilled water in a race motor as all the nasty stuff has been boiled away